There has hitherto been known a multi-layer piezoelectric element (hereafter sometimes referred to simply as an element) that comprises a multi-layer structure formed by stacking a plurality of piezoelectric material layers via internal electrode layers and a pair of external electrodes formed on side face of the multi-layer structure. The element generally has an opposing portion where the internal electrode layers oppose each other and non-opposing portions positioned on sides of both ends of the opposing portion in the stacked direction. When a voltage is applied to the element, the opposing portion undergoes displacement and the non-opposing portions do not undergo displacement, and therefore stress tends to be generated in a region around the interface between these sections. Therefore, there is disclosed an element that is designed for the purpose of reducing the stress generated around the interface by setting the modulus of elasticity of the non-opposing portions to be less than the modulus of elasticity of the opposing portion (Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Publication (Kokai) No. 2001-94164